Project Summary This project will use an activity space approach to explore differences in HIV/HCV injection risk behaviors and protective factors among people who use drugs (PWID) in Ukraine. Epidemiological reports estimate that over a third of PWID in Ukraine are HIV-positive, and 68% of PWID are HIV/HCV coinfected. The drug use context in Ukraine presents unique HIV/HCV prevention challenges. Unlike many places in the world, in Ukraine injection drugs are sold in liquid form. A dealer may distribute drugs by backloading or frontloading the solution into users' syringes, or users may purchase drugs in pre-loaded syringes or draw prepared drugs from a common container. Ukrainian PWID typically inject in groups of network members and use drugs in diverse places, including in homes, on streets, in clubs, and in vacant lots and alleys. Through their daily activities, PWID encounter various places with unique compositions of individuals who are engaged in protective or risk exacerbating behaviors. Moreover, social networks and place have been recognized as having important roles in shaping HIV/HCV risk behaviors. Drug users' social networks are not static across locations and have different qualities (e.g., levels of risk) based upon the composition of a network at a particular location and characteristics of that place (e.g., public or private). An ?activity space? refers to this unique combination of place, social network, and behavior that individuals have direct contact with as a result of their daily activities. The Specific Aims of this 2 year study are: 1) To describe the daily routine and daily path of PWID in Odesa, Ukraine, and adapt an Activity Space Inventory to the Ukrainian context; and 2) To examine differences in place and egocentric network characteristics by activity space. We will conduct in-depth interviews with 30 PWID in Odesa, Ukraine structured around daily routine (the activities that they engage in) and daily path (the specific places in which their activities occur) in order to understand the social and place-based contexts of PWIDs' lives, including both drug use and non-drug using activities. These data will be analyzed to examine HIV/HCV injection risk and protective behaviors by activity space. This information will then be used to quantitatively explore the relationship between place, social networks, and HIV/HCV risk among 150 PWID through an Activity Space Inventory. The unique aspects of drug use in Ukraine create acute challenges to the development of effective HIV/HCV prevention interventions for PWID. This study places PWID in a broader context that explores both their drug use related social networks, norms, and behaviors, and the non-drug use social context that may diminish or exacerbate HIV/HCV risk. Results will inform development and placement of intervention strategies tailored to specific drug use contexts and associated social network members and norms. .